(1) Field of the Invention
The present invention relates to ordnance, to explosives, and to thermic compositions and charges. The invention particularly relates to explosives where a fuel reacts with oxygen from standard environmental conditions, such as air or water, without ignition by a catalyst, pyrophoric material, or other fuel. The invention also relates to devices in which a material is heated within a container from which molten reactive particles are dispersed by an explosive or expulsion from a nozzle.
(2) Description of the Related Art
It is well-known to incorporate a metal fuel, such as aluminum, in energetic materials where, typically, particles of the fuel, when oxidized, provide a portion of the energy produced by the materials.
Heretofore however, in using such a metal fuel, it is mixed in particulate form, or otherwise combined, with an explosive, additional fuel, oxidizing and/or other materials. Examples are detonating substances such as HMX or RDX and substantially inert binders. For underwater use, such a metal fuel is, typically, provided with an oxidizer such as ammonium perchlorate, and a detonating substances with a substantial amount of oxidizer such as PBXN-111 or PBXN-103 are used.
These materials other than the metal fuel are disadvantageous to the extent that they take up a substantial part of the bulk and weight of a warhead or the like. Further, these materials are of relatively low density and strength and thus disadvantageous in a penetrating warhead.
When such a metal fuel is mixed with its dispersing and igniting explosive or other reactive material, the metal and material are limited to those that do not interact in storage or otherwise present a safety hazard. Also, such a mixed arrangement is undesirable since a dispersing charge cannot be removed from a warhead or other device to make it substantially inert.
It is known to disperse materials into an air or water environment for subsequent ignition and/or detonation as shown by the following seven United States patents:
U.S. Pat. No. 3,496,867 issued 24 Feb. 1970 to McDonald for “thermal radiation weapons” and discloses that combustible dusts and gaseous fuels have been mixed with air and detonated. Aluminum, magnesium, boron, boron carbide, zinc, and zirconium are mentioned as fuels, and these fuels are used with “a liquid combustible fuel” including pyrophoric substances to provide continuous ignition.
U.S. Pat. No. 3,685,453, which issued 22 Aug. 1972 to Hamrick for an “antipersonnel mine destruct system”, discloses pressurization, by gas from a gas generator, of “highly explosive gases” expelled from a nozzle for subsequent detonation by a high explosive charge.
U.S. Pat. No. 3,730,093 issued 1 May 1973 to Cummings for “explosive apparatus” and shows a fuel surrounded by high explosive whose implosion expels the fuel radially into a fuel-air cloud. Proposed solid fuels are materials, such as napthelene, “decomposable into detonable molecules”. The apparatus has a central tube filled with a mixture which undergoes a “thermit” reaction and is also dispersed by the detonation of the explosive into the dispersed fuel for ignition of the fuel-air cloud to overcome problems with timing such ignition after dispersion of the fuel has commenced.
U.S. Pat. No. 4,372,213, issued 8 Feb. 1983 to Rozner et al. for a “molten metal-liquid explosive method” and discloses a pyrotechnic pellet and igniter therefor within a casing, which may be aluminum placed in water. The pyrotechnic material may be composed of nickel, aluminum, and copper oxide powders. The pyrotechnic material melts the casing so that molten metals from the pellet and casing contact the water and cause an “energetic vapor or steam explosion”. It is stated that, although the cause of such explosions is unknown, they would provide “moderate sized high energy explosive devices.” A spatially inverse arrangement is also disclosed and has, from outside to inside, such pyrotechnic material, aluminum metal, and water.
U.S. Pat. No. 4,463,680 issued 7 Aug. 1984 to Sayles for a “method of generating single-event, unconfined fuel-air detonation” achieved by “simultaneous dispersion of both fuel and [an] initiating chemical catalyst into the atmosphere” where the fuel may be a “volatile liquid . . . aluminum, boron, or mixtures thereof”. However, the metal is intended to be always used in such liquid. An explosive disperses ferrocenyl catalyst into diesel fuel and disperses both into the atmosphere for “explosive detonation of the fuel-air mixture”.
U.S. Pat. No. 5,866,840 issued 2 Feb. 1999 to Briere et al. for “nozzles for pyrophoric IR decoy flares”, and discloses the expulsion of pyrophoric liquids, specifically alkyl aluminum compounds which burn with desirable IR emissions, from nozzles by a piston driven by gas from a gas generator.
U.S. Pat. No. 6,354,220 issued 12 Mar. 2002 to Graham et al. and discloses an “underwater explosive device” utilizing an explosive loaded with a metal such as titanium, magnesium or aluminum. It is stated that water can be an oxidizer for fuel-rich products of detonation, but does not give optimum results, a deficiency overcome by the provision of high pressure oxygen around the explosive.